for detecting microplastic particles in environmental samples at - - PowerPoint PPT Presentation

µFT-IR analytical approaches for detecting microplastic particles in environmental samples at Aarhus University

Jakob Strand

Aarhus University, Dept. Bioscience Danish Centre for Environment and Energy (DCE) Denmark Email: jak@bios.au.dk Presentation at NORMAN workshop

Dübendorf, Switzerland, 25/1-18

AARHUS UNIVERSITY

DEPARTMENT OF BIOSCIENCE

• 5. oktober 2017

Jakob Strand

Ongoing marine litter (incl. microplastic) activities at Aarhus University

We are involved in

• Research projects including µFT-IR method developments,
• Monitoring and more advisory-oriented projects for the Danish EPA

(incl. HELCOM and OSPAR WGs)

• Capacity building projects in third world countries (Zanzibar).

Marine litter topics includes: Beach litter surveys and source characterisation

• f macrolitter in Denmark, Greenland and Zanzibar.

Plastic particles in biota, e.g. in Greenlandic fulmars and mussels Microplastic, amounts and composition in water column, sediment, biota … and drinking water

AARHUS UNIVERSITY

DEPARTMENT OF BIOSCIENCE

• 5. oktober 2017

Jakob Strand

µFT-IR instrumentation

Agilent Cary 620/670 microscope with Focal Plane Array (FPA)

Available detection modes: Transmission and reflectance

128 x 128 pixels, wavelengths 3800 – 875 cm-1 15 x magnification, pixel size 5.5 x 5.5 µm Field of view: 700 x 700 µm Fast mapping of mosaic consisting of e.g. 64 field of views with area of ~5 x 5 mm = <2 hours (with 16 scans per pixel)

µATR (germanium coated)

64 x 64 pixel wavelengths 3800 – 875 cm-1 Pixel size 1.1 x 1.1 µm

Common ATR (GladiATR), 4000 – 400 cm-1

For particles with surface area > 0.5 mm2

In addition. Prototype Large Area ATR (Diamond/ZeSe) to be installed later this year

AARHUS UNIVERSITY

DEPARTMENT OF BIOSCIENCE

• 5. oktober 2017

Jakob Strand

Microplastic analyses >100 µm

Based on a combination of 1) Visual microscopy for chacterisation and quantification of potential MP particles in complex environmental samples

Characterisation performed according to JRC (2013).

And

2) µFT-IR analyses for validation of selected/representive potential MP particles transferred to a ZeSe disk or MirrIR slide

e.g. µFT-IR identification of cellulose-like fibres from blank samples

AARHUS UNIVERSITY

DEPARTMENT OF BIOSCIENCE

• 5. oktober 2017

Jakob Strand

Arctic study: Mikroplastic in sediment around Sisimiut city

Sisimiut

High levels of MP found in areas most impacted by harbour activities, effluents and run-off from city MP also found in samples from other areas except

• f one of two reference stations

Microplastic occur as Fibers, flakes, film, granules, and spherules in various colors

• NB. Foreløbige resultater

AARHUS UNIVERSITY

DEPARTMENT OF BIOSCIENCE

• 5. oktober 2017

Jakob Strand

Microplastic analyses >100 µm

Reflectance with MirrIR slide Based on mosaic with several isolated particles

AARHUS UNIVERSITY

DEPARTMENT OF BIOSCIENCE

• 5. oktober 2017

Jakob Strand

Composition of microplastic in sediment from sisimiut characterised based on their polymers

Dominated by: Polyester (PET), Polyacrylate (e.g. paint flakes), Polyolefins/polyvinyls, Rubber (e.g. from tyres) Most MP in sediments from Sisimiut consist of polymers with densities >1 g/cm3, dvs. more likely to sink to sea floor.

n = 154 partikler analyseret med FT-IR

AARHUS UNIVERSITY

DEPARTMENT OF BIOSCIENCE

• 5. oktober 2017

Jakob Strand

Microplastic analyses <100 µm

Two approaches explored … for now 1) Use of Anodisc membrane filter (0.2 µm): Wavelengths: 3800 – 1300 cm-1, i.e. more limited

2) Settlement of 100 µl particle suspension in ethanol transfered to a ZnSe disk Wavelengths: 3800 – 875 cm-1 Limitation: Difficult to take a small representative subsample from a particle suspension in ethanol

First with Anodisc identified as polyacrylate Later with ATR identified as PTFE with trace of acrylate?

AARHUS UNIVERSITY

DEPARTMENT OF BIOSCIENCE

• 5. oktober 2017

Jakob Strand

Some challenges to work on …

Reliable quantification incl. assessments of analytical uncertainty and other relevant QA, e.g. using internal standard addition with known reference particles and (internal) reference materials. More automated algorithms for polymer recognition of various types of MP particles in mosaic maps based on chemometric analyses. Establish a functional internal spectra library that is not that expensive, so it can also better can be used for student projects – do you have a suggestion for this ?

Thanks for your attention !